Question

In python, please help me fill in these functions given their limitations.

def positionalSum(a, b):

"""

Given 2 lists, add the 2 lists together. The list will be as long as the shortest list.

Input: 2 lists of numbers

Return: A new list of the size of the smaller list of the 2 lists added together positional.

Example:

>>> positionalSum([1, 2, 3, 4], [4, 3, 2]) # [5, 5, 5]

>>> positionalSum([1, 2, 3, 4], [1, 1, 1, 4]) # [2, 3, 4, 8]

"""

pass

def scalarMatrix(n, m):

"""

Given a matrix, size a x b, multiply each position by n.

Input: an number to multiply each item in the matrix (list of list)

Return: A new list of lists that multiplies all values by n

Limitation: No using numpy

Examples: n = 3

[[4, 4, 4]

[1, 2, 4]

[10, -1, 2]]

Result:

[[12, 12, 12]

[3, 6, 12]

[30, -3, 6]]

"""

pass

def isSubString(sub, longStr):

"""

Determine if a string exists in another string.

Not allowed to check for direct membership. You need to use looping

Input: 2 strings

Returns: Boolean if there is substring.

Limitation: No "in" membership

Example:

>>> isSubString("cat", "Concatenate") # True

>>> isSubString("orange", "Concatenate") # False

>>> isSubString("acsd", "car") # False

"""

pass

def whereSubString(sub, longStr):

"""

Determine last position of the start of a substring occurs.

Not allowed to check for direct membership. You need to use looping

Input: 2 strings

Returns: Integer showing where the substring starts in the longStr. Return -1 if

the substring doesn't exist

Limitation: No "in" membership

Example:

>>> whereSubString("cat", "Concatenate") # 3

>>> whereSubString("orange", "Concatenate") # -1

>>> whereSubString("acsd", "car") # -1

"""

pass

Answer 1

def positionalSum(a, b):
if len(a)>len(b): #check for the smaller list
for i in range(len(b)): #traverse the list as per the length of list
b[i]+=a[i] #add element from the longer list to the shorter one
return b #return the horter list
elif len(a)<len(b):
  
for i in range(len(a)):
a[i]+=b[i]
return a
else:
for i in range(len(a)):
a[i]+=b[i]
return a

def scalarMatrix(n, m):
y=[] #an empty list which will get appended with the sub lists to create the 2d matrix
for i in m: #traverse the list entered
z=[] #empty list which will be loaded with elements and re-intialized to empty list onceappended to the y list
for j in i: #traverse elements of sub-list
z.append(j*n) #multiply each element with the entered number and append to z
y.append(z) #once all memebers of the sub-list are multiplied and z is created, it will be appened to the y list
return y

def isSubString(sub, longStr):
for j in range(len(longStr)): #traverse the longer string as per the length of string
#if the first alphabet of sub matched with a alphabet in longstr then check the subsequent string of sub's length
#if it matches completely with sub
if(sub[0]==longStr[j] and sub==longStr[j:j+len(sub)]):
return True
return False

def whereSubString(sub, longStr):
for j in range(len(longStr)):
if(sub[0]==longStr[j] and sub==longStr[j:j+len(sub)]):
return j
return -1